Jack-screw



(No Model.)

B. E. REEVES.

No. 273,894. Jvllatented Mar. 13,1883.

J@ y fr E!! f um!!! uw i; EEE Zr 1 a/ n f A nally in said casin.

'UNITED STATES VPnrniwr Fries.

BENJAMIN F. REEVES, OF TUGKAHOE, NEW JERSEY.

JACK==SCREW.

SPECIFICATION forming part of Letters Patent No. 273,894, dated March13, 1883.

Application filed February 1, 1883. (No model.)

To all lwhom it 'may concern Be it known that l, BENJAMIN F. REEVES, acitizen of the United States of America, residing atTuckahoe, in thecounty of Cape May and State ofNew Jersey, have invented certain new anduseful Improvements in Jack-Screws; and l do hereby declare thefollowing'to be a full, clear, and exactdescription of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,and to letters or figures of reference marked thereon,which form a. partof this specification.

This invention relates to an apparatus for lifting weights shortdistances or long distances by long steps, its object being to pro` videfor this purpose a powerful and compact apparatus, which may be readilyadjusted to its work and operated by a small expenditure of manuallabor.

The invention consists in certain novel comf 'binations of devices,which will be hereinafter particularly described, and pointed out in theappended claims.

In the accompanying drawings, Figure l is a vertical longitudinalsection of a. lilting apparatus constructed according to my invention.Fig. 2 is a section on linew, Fig. 1. Fig. 3 is a similar section online y y, Fig. l. Fig. 4 is a fragmentary longitudinal section taken ona horizontal plane above one of the carriages. Fig. 5 is a view of theratchet-lever by which the operating-screw is turned.

The letter A indicates an oblong casing with vertical side walls, a, endwalls, c', and base b. The top of this casing is open, except for anarrow inwardly-projecting rim, c. Within the casing are twostrongly-constructed carriages, D and D', arranged to travel longitudi-Each of these carriages is composed of two side plates, d, and an endplate, d', and two traveling rollers, e, provided with journals havingbearings in the opposite plates, d d, while their peripheries rest onthe base b.

Above and preferably over the space between the two traveling rollerseach carriage is provided with a. lifting-roller, f, of greater diameterthan thevtraveling rollers, and also journaled between the oppositeplates, d d.

Both the traveling and lifting rollers are grooved circumferentially, asshown at g and g', to permit the pass-.ige of a screw-shaft, H, thejournals of which have their bearings in the opposite end walls, ca, ofthe casing, the projecting ends of said shaft being squared to receivethe ratchet-wrench I, the construction of which will be readilyunderstood by reference to Fig. 5.

The screw shaft H has two screw-threads, h and h', on opposite sides ot'its middle portion, and these two screw-threads are pitched in oppositedirections and play through correspondingly-threaded apertures in theend plates, d', of the carriages D and D', respectively, so that whenthe screwshatt is turned in one direc tion the carria ges will approacheachother and recede from each other when it is turned in the oppositedirection.

The letter L indicates the lifting-platform, the horizontal top of whichis of a size and shape to tit in the space within the rim c, and itslower surface is formed by two downwardly and inwardly inclined faces, it', which meet under the center of the top, thus giving the platform asa whole the shape of an obtuse isosceles triangle with its base turnedupward. The inclined faces of the platform rest upon the lifting-rollersf of the carriages D and D', respectively, and through the lower part ofthe platform is formed a longitudinal slot or passage, as indicated atS, the open ends of which coincide with the grooves in said rollers. Theslot S divides the lower part of the platform into two portions, betweenwhich passes the screw-shaft H, this slot permitting a vertical play ofthe platform approximately equal to the weight of the casing withoutinterference by the screwfshaft.

The letter W indicates a weight placed upon the platform as if to beraised thereby.

It is now obvious that it' the screw-shaft H be turned in a direction tocause the carriages D and Dl to approach each other, theinclined facesof the platform will ride upward on the liftin g-rollers ff ot'saidcarriages, and the platform be thereby raised and lift the weight. Ifthe upward stroke or play of the platform is not sufficient to lift. theweight to the desired height, said weight may be blocked up, theplatform lowered, and blocks placed upon it IOO still higher.

Having now described my invention and eX- plained the operation thereof,I wish it to be understood that I do not confine mysel f to the preciseconstruction and arrangement of parts shown in the drawings, but mayvary the same iu any desired manner Without departing from the essentialprinciples of the invention. .For instance, I may use a lifting-carriageunder only one of the inclined faces of the platform,Y and thus lift theplatform at one end for prying up heavy Weights, and I may mount oneplatform upon another, providing the upper platform withliftingcarriages which travel upon the lower, said platforms beingraised successively. Again, I may provide the carriages with detachableclutches for engaging them with the scre\v-shat't, so that bydisengaging said clutches from the shaft the carriages may be quicklyrun back to their starting-points Without the lossof time Which would beoccasioned by running them back bymeans of screws.

What I claimis 1, In a lifting apparatus, the combination, with aplatform having one or more inclined under faces, of one or moretraversing carriages provided with a roller or rollers arranged to bearagainst said inclined face or faces, and means for driving said carriageor carriages under and against said inclined face or faces for liftingthe platform, substantially as described.

2. vThe combination, with the platform L,

-2 wasn having inclined under faces, it', of the carriages D D', havingthe lifting-rollers ff, arranged to bear against said inclined faces,and mechanism for causing said carriages to approach and recede fromeach other, substantially as described.

3. The combination, with the platform L, having the inclined underfaces, z' t', and the carri-a ges havin g the liftin g-rollers f f,arranged to bear against said inclined faces, respectively,of thescrew-shaft H, mounted in suitable.

bearings, and having the oppositely-pitched threads engaging with saidcarriages, respectively, substantially as described, and for the purposeset forth.

4. The combination, with thecarriages DD, having the grooved travelingand lifting rollers, ot' the double screw-shaft H,*in engagement withsaid carriages,and passing through the grooves in said rollers,substantially as described.

5. The combination, with the carriages DD and the screw-shaft H, inengagement with and extending between said carriages, of thelifting-rollers ff, and the platform L, having the inclined under faces,i z', resting upon said rollers and slotted longitudinally to permit thepassage of the screw-shaf't, substantially as and for the purpose setforth.

In testimony whereofI affix my signature in presence of two witnesses.

BENJAMIN FURNACE REEVES. Y

NVitnesses:

JOSEPH C. MARSHALL, E. E. GoFF.

